Stencil clamping device for duplicating machines



Oct. 20, 1953 J. w. LlNS LEY, JR. 2,655,866

STENCIL CLAMPING DEVICE FOR DUPLICATING MACHINES Filed Feb. 8, 1950 2 Sheets-Sheet l Q N \s ATTORNEY Oct. 20, 1953 J. w. LINSLEY, JR 2,655,866

STENCIL CLAMPING DEVICE FOR DUPLICATING MACHINES Filed Feb. 8, 1950 2 Sheets-Sheet 2 IIIIIIIIIIII I" Patented Oct. 20, 1953 UNITED STATES TENT OFFICE STENCIL CLAMPIN G DEVICE FOR DUPLICATIN G MACHINES Application February 8, 1950, Serial No. 142,976

7 Claims.

This invention relates to duplicating machines and more particularly to a clamping device for clamping a stencil on a drum of a stencil type duplicating machine.

It is an object of the present invention to provide an effective and emcient clamping device for expediting the application, alignment and clamping of a stencil to a drum of a duplicating machine.

In accordance with one embodiment of the invention, the drum of a stencil type duplicating machine is provided with a flat relatively stationary jaw extending inwardly from the periphcry of the drum and an oscillatable flat jaw adapted to cooperate with the stationary jaw to grip one end of the stencil therebetween. The oscillatable jaw is movable to and from closed and open positions under control of an actuating lever and in open position it forms, in cooperation with the stationary jaw, a V-shaped recess in the drum for receiving the forward end of the stencil in the bottom thereof to position a plurality of apertures in the end portion of the stencil in engagement with a plurality of stencil aligning pins formed on the stationary jaw. A pair of side guides mounted on the end of the oscillatable jaw serve to position the stencil laterally in the V-shaped recess so that a stencil which has been moved into position in the bottom of the V-shaped recess need only be partially retracted to automatically move the ends of the apertures in the stencil into engagement with the locating pins to align the stencil relative to the drum, after which the stencil may be wrapped around the drum and the lever actuated to clamp the stencil on the drum.

Other objects and advantages of the invention will be apparent by reference to the following detailed description thereof and the accompanying drawings illustrating one embodiment in which Fig. 1 is a somewhat schematic elevational sectional view of a portion of a duplicating machine with the invention applied thereto;

Fig. 2 is an enlarged transverse sectional view of a portion of the drum and the stencil clamping device of the machine with the movable jaw of the clamping device in open position and showing, in full lines, a stencil being inserted in the clamping device with a downward motion to establish an interlocking connection with the aligning pins formed on the stationary jaw of the clamping device and showing, in dot and dash lines, a stencil positioned adjacent and parallel to the face of the movable jaw in a position to be removed from the clamping device;

Fig. 3 is a view similar to Fig. 2 showing, in full lines and in dotted lines, two positions that a stencil might occupy after being moved upwardly into engagement with the aligning pins of the clamping device;

Fig. 4 is a sectional view similar to Figs. 2 and 3, but taken in a plane intermediate the pins on the drum and showing the movable jaw in closed position clamping the stencil against the stationary jaws;

Fig. 5 is a plan or face view of a portion of the drum and the clamping mechanism indicated by the lines 55 of Fig. 1;

Fig. 6 is a longitudinal sectional view through a portion of the drum taken on the line 5-5 of Fig. 4 with parts broken away;

Fig. '7 is a fragmentary sectional view through a portion of the clamping mechanism taken on the line 1-7 of Figs. 4 and 6; and

Fig. 8 is a face view of an end portion of a stencil with parts broken away.

Referring to the drawings, Fig. 1 illustrates diagrammatically a duplicating machine it comprising a drum I2 mounted on a shaft I4 which, in turn, is mounted in suitable side frames (not shown) for rotatably supporting the drum I2 for rotation about its axis. The peripheral supporting wall I5 of the drum I2 is perforated and is adapted to support thereon a stencil I5, which is secured at its forward end to the drum by a clamping device I'l. The stencil IE is a composite structure of the type having a thin stencil sheet I8, in which the indicia is out, typed, or otherwise impressed, and which is attached at its forward end to a relatively stiff paper backing sheet I9. The backing sheet I9 has an end portion 29 extending beyond the end of the sheet It, which end portion 20 is adapted to be gripped by the clamping mechanism I7 and has a row of apertures or keyhole slots 2i formed therein and a transverse row of perforations 22, which permits the major portion of the backing sheet to be torn off to expose the stencil sheet I8 after the stencil has been applied to the drum I 2.

Inking means (not shown) is provided to supply ink to the inner side of the stencil so that, as the drum I2 is rotated and the stencil I8 thereon engages successive sheets of paper 24 fed between the drum l2 and a table 25 in timed relation with the rotation of the drum, the ink will pass through the openings formed in the stencil I8 and be transferred to the sheets of paper 2 1, as is usual in this method of application.

The stencil clamping device I? comprises a stationary jaw 28 and a jaw 30 movable to and from a closed position, indicated in Fig. l, and an open position, indicated in Figs. 2 and 3. The stationary jaw comprises a flat plate or wall 3|, which extends between the end walls 32-32 of the drum, and is directed obliquely inwardly from the periphery of the drum. The fiat face 34 on the stationary jaw forms a continuation of the stencil supporting surface of the wall I and, in cooperation therewith, defines an edge or corner 38 over which the stencil is bent, as indicated in Fig. 4.

The movable jaw 30 may be in the form of a casting having a straight wall 40 with a fiat stencil engaging surface 52 thereon, between which surface and the surface 34 the forward end of the stencil is gripped when the movable jaw 30 is in its closed position. A wall 44, having the same curvature as the drum 12, may be formed on the movable jaw 30 and the walls 40 and 44, :at their ends, are connected to end walls 56-56, from which project trunnions 4848 rotatably mounted in bearing apertures 49-49 in the end walls 32 of the drum. The trunnions 48 rotatably support the movable jaw for oscillation about an axis 50 parallel to the axis of the drum and. located substantially in the planes of the flat faces 42 and 34 of the stationary and movable jaws. The axis 50 coincides with the bottom of the V- shaped recess 5| formed by the movable and stationary jaws 30 and 28, respectively, when the movable jaw is in open position. Extensions or wing portions 52 (Fig. '7) of the end wall 46 form side guides spaced apart sufficiently to receive the stencil therebetween and to position it laterally on the drum.

A plurality of pins or abutments 56 are formed in a row on the stationary jaw 28 in laterally spaced relation to each other corresponding to the spaced relation of the keyhole slots 2| in the forward marginal portion 20 of the stencil It. The abutments 56 are relatively narrow, as viewed from the front, and are triangular in shape, as viewed from the end of the drum, having a stop surface or shoulder 51 extending substantialhr perpendicular to the surface 34 and having a surface 58 sloping at an acute angle from the surface 34. Recesses 59 are provided in the movable jaw 30 to form clearance for, and receive the abutments 56 therein when the movable jaw is in its closed position. The row of abutments 56 are positioned on the stationary jaw 28, a predetermined distance from the axis 50 and are positioned so as to provide a space between themselves and the face 42 of the movable jaw 30 when the movable jaw is in its opened position, as indicated in Fig. 2.

The relation of the abutments 56 to the surface 42 of the movable jaw and the bottom of the V-shaped recess 5| formed by the stationary and movable jaws is such that when a stencil is moved endwise into the recess in a direction substantially parallel to the surface 34, as indicated in full lines in Fig. 2, the forward portion of the stencil will engage the sloping surface 42' and be guided thereby toward the wall 3| of the stationary jaw and into engagement with the abutments 56 thereon to establish an interlocking relationship between the keyhole slots 2| in the stencil and the abutments 56. The sloping wall 42 of the movable jaw serves not only to direct the lower end of the stencil toward the wall 3| and into engagement with the abutments 56 as the stencil is inserted, but also serves, as the stenoil is moved upwardly in a reverse direction, to prevent the lateral movement of the lower portion of the stencil from the wall 3| which would permit disengagement of the stencil from the abutments as the operator applies the stencil to the drum. In order to remove the stencil from the clamping mechanism, with the jaw in its open position, the stencil may be moved against or adjacent to the surface 42 of the movable jaw, as indicated in dot and dash lines in Fig. 2, and moved outwardly parallel to the surface 42 in a direction indicated by the dotted arrow. With the stencil in the position indicated in dotted lines in Fig. 2, there is ample clearance between the stencil and the abutments 56 to permit the removal of the stencil.

If desired, laterally projecting shoulders or stop surfaces 60 may be formed on one or the other or both of the movable and stationary jaws to aid in forming a positive stop at the bottom of the V-shaped recess 5|. The stop 60 may be formed in any suitable manner and, as shown herein, comprises a plurality of members formed on the stationary jaw 28 and positioned below the abutments 58, the walls 40 of the movable jaw 30 being recessed to provide clearance therefor.

Any suitable mechanism may be employed for actuating the movable jaw to and from its open and closed positions. In the embodiment shown, the movable jaw 30 is provided with a pin 62 extending from one end thereof and pivotally connected to one end of a link 63, which, at its other end 64, is pivotally connected toan operating lever 65. The lever 65 is fulcrumed at 66 to one end wall 32 and is movable to and from the dotted and full lines shown in Fig. 1 to impart movement to the movable jaw 30 to and from open and closed positions and serves to hold the movable jaw in either position. A resilient spring or stop member 68, engageable with a shoulder 69 on the lever 14, serves to hold the lever in its operating position and maintains the movable jaw 30 in its closed position.

In applying a stencil to the drum 12- on the duplicating machine, assuming the drum to be in the position shown in Fig. l, the operator may hold the stencil at its rear longitudinal end portion between the thumb and fingers of his right hand, and move the forward end thereof downwardly toward the V-shaped recess 5| and, with the stencil turned slightly to position the longitudinal edges thereof obliquely to the end planes of the drum, enter one forward corner portion of the stencil into the recess 5| and, with a lateral movement of the forward portion of the stencil, move it into engagement with one of the side guides 52, and then, by turning the rear portion of the stencil so that its longitudinal edges are approximately parallel with the end planes of the drum, the other forward corner portion of the stencil. will be moved into the recess 5|. Once the forward end of' the stencil has been entered in the recess 5| of the drum, it is only necessary for the operator to push the stencil downward until it contacts the bottom thereof and then pull the stencil in a reverse direction substantially parallel to the surface 34, which reverse movement will automatically engage all of the stencil keyhole slots with their respective abutments 56 and cause the accurate alignment of the stencil relative to the. drum. The stencil may then be partially wound around the drum with the right hand and the partially wound portion smoothed down with the left hand while the right hand releases the end of the stencil and actuates the lever 65 to close the movable jaw 30 as the remainder of the stencil. is being smoothed down on the drum with the left hand. With the movable jaw 30 closed, the leading end of the stencil is firmly gripped in position on the drum and the main body portion of the backing sheet l9 may be removed by tearing it along the line of perforations 22 and against the edge of the movable jaw 39 to expose the stencil sheet is preparatory to operating the duplicating machine.

' It is to be understood that the above-described arrangement are simply illustrative of the application of the principles of the invention. Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed is:

1. A device for clamping a sheet having a plurality of apertures adjacent one end thereof to a drum comprising a drum having a cylindrical surface for supporting said sheet, a stationary jaw on said drum extending inwardly from said cylindrical surface, an oscillatable jaw mounted on said drum and engageable with said stationary jaw to grip said sheet therebetween, a plurality of abutments on said stationary jaw adapted to engage said sheet in the apertures therein to align the sheet on the drum, and means mounted on said drum for rotation therewith for moving said oscillatable jaw to and from closed and open positions, said jaws having substantially flat surfaces which, when the oscillatable jaw is in open position, forms a V-shaped recess in said drum having a bottom in predetermined relation to said abutments for causing the apertures in a sheet disposed in the bottom of said recess and in a position substantially parallel to the face of said stationary jaw to be engaged by said abutments.

2. In a duplicating machine of the type using a stencil provided with a row of closed slots adjacent the forward edge thereof, the combination of a drum having a peripheral surface and an axially extending edge for supporting the stencil, a stationary jaw having a flat surface extending inwardly from said edge of the peripheral supporting surface and forming a continuation thereof, a movable jaw having a flat surface movable toward the fiat surface of the stationary jaw for gripping the stencil therebetween, means mounting the movable jaw for oscillatable movement about an axis passing substantially through the plane of the flat surfaces of said movable and stationary jaws and parallel to the axis of said drum, actuating means mounted on said drum for rotation therewith for moving said movable jaw to and from open and closed positions, the flat surfaces of said movable and stationary jaws, with the movable jaw in open position, forming a V-shaped recess having a bottom for supporting in predetermined relation to said drum a stencil positioned therein substantially parallel to the surface of said stationary jaw, a plurality of stencil aligning abutments arranged in a row on said stationary jaw and in axially spaced relation to each other corresponding to the spacing of the slots in said stencil and engageable with the slots for positioning the stencil on said drum, said abutments being positioned in predetermined relation to the bottom of said V-shaped recess and in spaced relation to said movable jaw when said movable jaw is in open position, sloping surfaces on said abutments extending from the flat surface of the stationary jaw for guiding around said abutments the end portion of sten- 6. oils moved into said V-shaped recess in a direc-- tion substantially parallel to the stationary jaw, the arrangement of the parts being such that when a stencil is moved in a direction parallel to the face of the stationary jaw into said V-shaped recess the forward edge thereof is engaged by the movable jaw and directed into the bottom thereof and toward said stationary jaw to cause the slots in said stencil to engage portions of the abutments.

3. In a duplicating machine of the type using a stencil provided with a plurality of apertures adjacent one end thereof, the combination of a drum having a stencil supporting cylindrical surface, a stationary jaw on said drum extending inwardly from the cylindrical surface, a movable jaw engageable with said stationary jaw to grip a stencil therebetween, means mounting said movable jaw on said drum for oscillatable movement, means for moving said movable jaw to and from closed and open positions, a pair of side guides, mean mounting said side guides in a predetermined position laterally relative to said drum for positioning said stencil laterally on said drum, and a plurality of stencil aligning pins on said stationary jaw adapted to engage said stencil in the apertures therein to align said stencil relative to said drum, said jaws, with the movable jaw in open position, forming a V-shaped recess having a bottom in predetermined relation to said pins whereby a stencil moved in a direc tion parallel to said stationary jaw into said recess engages the oscillatable jaw and is guided thereby into the bottom of the recess and toward the stationary jaw to cause the apertures in the stencil to be engaged by portions of said pins.

4. A device for clamping a stencil having a plurality of apertures adjacent one end thereof to a drum comprising a drum having a cylindrical surface for supporting a stencil, a stationary jaw on said drum having a flat face extending inwardly from said cylindrical surface in a plane parallel with the axis of said drum, a movable jaw having a flat face engageable with the flat face of the stationary jaw for gripping a stencil therebetween, means mounting said movable jaw for oscillatory movement about an axis disposed substantially in the planes of said flat faces and parallel to the axis of said drum, a plurality of stencil aligning pins on said stationary jaw adapted to engage said stencil in the apertures therein to align the stencil relative to said drum, and side guides mounted on one of said jaw members adapted to engage said stencil and position it laterally relative to the drum, said jaws, with the movable jaw in open position, forming a V- shaped recess having a bottom in predetermined relation to said aligning pins whereby, when a sheet is moved parallel to said face on said stationary jaw into said V-shaped recess, the forward end of the stencil will engage the fiat face of the movable jaw and be guided thereby into the bottom of the recess and toward said stationary jaw to cause the engagement of the apertures therein by portions of said aligning pins.

5. A device for clamping a stencil having a plu-' rality of apertures adjacent one end thereof to a drum of a duplicating machine comprising a drum having a peripheral surface and an axially extending edge for supporting the stencil, a stationary jaw having a flat face extending inwardly from the edge of the peripheral supporting surface and forming a continuation thereof, a movable jaw having a flat face engageable with the flat face of the stationary jaw for clamping a stencil therebetween, means mounting said movable jaw for oscillatable movement about an axis disposed substantially in the planes of said flat faces and parallel to the axis of said drum, means including an actuating lever mounted on the end of said drum for moving said movable jaw' to and from open and closed positions, the flat faces of said jaws with the movable jaw in open position forming a V-shaped recess having a bottom for supporting in predetermined relation to said drum a stencil positioned in the recess in substantially'parallel relation to the face of said stationary jaw, a member on at least one of said jaws having a surface extending transversely from the flat face of the jaw and through the axis of rotation of the movable jaw and engageable with the end of a stencil positioned in the bottom of said V-shaped recess, a plurality of stencil aligning pins on said stationary jaw adapted to engage said stencil in the apertures therein to align the stencil relative to said drum, said pins being positioned in predetermined spaced relation to the bottom of said V-shaped recess and in spaced relation to said movable jaw when said movable jaw is in open position, and sloping surfaces on said aligning pins extending from the fiat surface of the stationary jaw for guiding around said pins the end portion of a stencil moved into the bottom of said V-shaped recess in a direction substantially parallel to the stationary jaw, the arrangement of parts being such that when a stencil is moved in a direction substantially parallel to the face of the stationary jaw into said V-Shaped recess the forward. edge thereof is engaged by the movable jaw and. directed toward said stationary jaw and into the bottom of the recess to cause the apertures in said stencil to engage portions of the aligning pins.

6. In a duplicating machine, the combination of a drum having a sheet supporting peripheral surface and a stationary jaw with a substantially fiat face extending inwardly from said surface, a movable jaw with a substantially flat face mounted on said drum for oscillating movement from an open position to a closed position in engagement with said stationary jaw for gripping a sheet therebetween, means mounted on said drum for rotation therewith for moving said movable jaw to and from open and closed positions and for looking said movable jaw in closed position, means for limiting the movement of said movable jaw from closed position to open position to position said jaws at an oblique angle relative to each other to form a V-shaped recess having a bottom for supporting the end of a sheet therein, a plurality of sheet aligning pins positioned on said stationary jaw in predetermined spaced relation to the bottom of said V-shaped recess and in spaced relation to said movable jaw in its open position, said aligning pins being adapted toengage said sheet in a plurality of apertures provided in the end portion of the sheet for aligning said sheet relative to the drum and having surfaces slopingfrom' said stationary jaw for guiding the end of a sheet 8, over said pins when said sheet is moved into said recess in a direction substantially parallel with said stationary jaw, the arrangement of the parts being such that, when a sheet is moved into the bottom of said recess in a direction substantially parallel to' the stationary jaw, the end portion of the sheet is moved toward said stationary jaw to cause the engagement of the apertures therein with said aligning pins.

7. In a duplicating machine, the combination of a drum having a sheet supporting peripheral surface and a stationary jaw extending inwardly from said surface, a movable jaw mounted on said drum for oscillatable movement from an open position to a closed position in engagement with said stationary jaw for gripping a sheet therebetween, means for locking said movable jaw in closed position, means for limiting the movement of said movable jaw from closed position to open position to position said jaws at an oblique angle relative to each other to form a V-shaped recess having a bottom for supporting the end of a sheet therein, a pair of side guides engageable with the side edges of said sheet, means mounting said side guides on one of said jaws to position a sheet laterally relative to said drum, a plurality of sheet aligning pins positioned on said stationary jaw in predetermined spaced relation to the bottom of said V-shaped recess and in spaced relation to,

said movable jaw in its open position, said aligning pins being adapted to engage said sheet in a plurality of apertures provided in the end portion of the sheet for aligning said sheet relative to the drum and having surfaces sloping from said stationary jaw for guiding the end of a sheet over said pins when said sheet is moved into said recess in a direction substantially parallel with said stationary jaw, the arrangement of the parts being such that, when a sheet is moved into the bottom of said recess in a direction'substantially parallel to the stationary jaw, the end portion of the sheet is moved toward said stationary jaw to cause the engagement of the apertures therein with said aligning pins.

JOHN W. LINSLEY, J R.

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